It’s natural to fixate on the hands you lose. Victories are fleeting, and are what’s “supposed” to happen, so they don’t stick in the mind as much as a bad beat or badly played hand that costs you a lot of chips.
It’s good to study both the hands you win and the hands you lose, in order to improve your game. You can learn from your mistakes. Some hands you win for a big pot are good outcomes on bad play, and some lost hands are played perfectly and yet have a bad outcome. Sometimes when you win, you don’t get as many chips as you could have if you had played the hand better. There’s always something to learn, and sometimes the lessons aren’t apparent when the hand is fresh, but when you go back later you can pick up things you couldn’t see at the time when you had less experience. I think it’s probably better to focus on your bad plays and mistakes and close holes in your game first. It’s one of the reasons I post so many hands where I lose (and lose because I made a mistake) on these forums, and not so many hands where I played brilliantly.